Hand screed for the placement of concrete



C. JACKSON HAND SCREED FOR THE PLACEMENT OF CONCRETE Deg 22, 1942.

Filed July 5, 1941 INV ENT OR. Y Cora/1'1! c/Zzc 60/2 ATTORNEYS.

Patented Dec. 22, 1942 HAND SCREED FOR THE PLACEMENT OF CONCRETE- Corwill Jackson, Ludington, Mich.

Application ,July 5, 1941, Serial No. 401,181

9 Claims.

This invention relates to improvements in hand screeds for the placement of concrete.

The main objects of this invention are:

First, to provide a vibratory hand screed for the placement of concrete in floors, decks, roofs, and in various other relations where concrete surfaces of substantial area are to be produced which is highly efficient and easy to operate under. varying conditions.

Second, to provide a structure in which handles are adjustably mounted so that they may be quickly adjusted to position, permitting operation of the screed with an end closely adjacent to a wall or other structural part such for example. as the side structure of a bridge.

Third, to provide a structure in which the vibratory action of the screed tends very substantially to propel it along the surface being screeded, thus minimizing efiort.

Fourth, to provide a structure in which the handles are so arranged that a minimum of effort is required in holding the screed upright and manipulating it.

Objects relating to details and economies of the invention will appear from the description to follow. The invention is defined in the claims.

A preferred embtfdiment of the invention is illustrated in the accompanying drawing. in which:

Fig. 1 is a fragmentary side elevation of a preferred embodiment of my invention, an adjusted position of one handle being indicated by dotted lines at one end of the screed.

Fig. 2 is an end elevation of the screed showing its operative relation to concrete material being screeded.

Fig. 3 is an enlarged fragmentary section on 11 line 3-3 of Figs. 1 and 2.

Fig. 4 is an enlarged fragmentary view partially in section on line 4-4 of Fig. 1.

In the embodiment illustrated the flat or plank-like screed member I is formed of Wood, being of substantial width and is disposed vertically edgewise. The length of course depends more or less upon the particular use desired and the width of ten or twelve inches and thickness of about two inches is quite satisfactory for most purposes. If the lengthof the screed were extended beyond the neighborhood of ten or twelve feet it would be desirable to increase both the width and the thickness.

The screed member is provided with handle units or assemblies at each end designed for the purpose of ease in manipulation--that is, maintaining the screed in upright position and the manipulation thereof, eliminating transmission of objectionable vibrations to the operator, and adjustment which permits the convenient use of the screed by different operators and also different operating conditions.

The handle assembly of the embodiment illustrated comprises angled brackets 2 provided with studs 3. These angled brackets are arranged in spaced pairs on both sides of the screed member and adjacent each end thereof. The corresponding brackets of the pairs are arranged in transverse alignment and are secured to the screed member by means of bolts 4 which are arranged through the screed member as clearly shown in Fig. 4'.

The flexible tubular support members 5 are sleeved upon the studs 3 and clamped thereon by means of the band clamps B; the clamp having ears receiving clamping bolts as is illustrated in the drawing, These support members 5 are of substantial length so that the handle coupling members I may be clamped thereto intermediate the brackets and in substantially spaced relation thereto. These coupling members are secured to the tubular support members by means of pairs of clamps 8 encircling the support members. The clamps are attached at their upper ends to the coupling members and at their lower ends to one another by the bolts shown in Figs. 1 and 2.

The support members are formed of lengths of fabric reinforced tubing or hose of suitable dimensions to provide a relatively secure stable support while damping the vibrations imparted to the screed member by the vibrating unit 9.

The handles comprise pairs of shait members Ill and the handle bars II at their outer ends. These shaft members are connected to the handles by means of clamps l2 which permits spacing adjustment of the handle shaft members.

The handle shaft members are pivotally connected to the coupling members 1 at l3 and secured in their adjusted positions on their pivots by means of bolts 14 which engage the segmental slots I5 in the coupling plates or members, see Figs. 1 and 3, these slots being concentric with the pivots I 3 so that by loosening the bolts the handles may be adjusted and then securely clamped in their adjusted positions.

This adjustment permits the handles being adjusted to positions shown in Fig. l which is a central position of adjustment or they may be adjusted to upright position as shown by dotted lines at IS in Fig. 1, or they may be substantially lowered beyond the position shown in illustrated, the vibrating element or unit 9 being p an electric motor provided with a rotor having an unbalancing weight l8. This vibrating unit is mounted on one side of the screed member by means of brackets l9 and is disposed with its axis in parallel relation to the screed. One' ad vantage of this arrangement is that the vibratory impulses tend very substantially to propel the screed over the surface being screeded, the direction of travel depending upon the direction of rotation of the unbalancing rotor.

The screed is vibrated at high frequency and this high frequency vibration greatly increases the screeding capacity of the screed as it substantially act to bring the mortar to the surface and to render relatively dry concrete mixtures fluid or semi-fluid and workable. It will be understood of course that this screed is designed primarily for screeding and finishing. I illustrate it in operative relation to material being screeded in Fig. 2.

The use of wood in the screeding member is of very substantial advantage a the vibrations are effectively transmitted from the vibratory motor throughout the length of the screed even up to twenty feet in length and froma relatively small vibratory motor. Were steel to be employed in a screed of this type and of that length or approximately that length the vibrations would fade out in certain zones unless of course the structure be made unduly heavy. Wood has the further advantage of lightness in connection with it abiity to uniformly transmit vibrations. If desired, a metal shoe may be provided for, but this is not commonly found necessary or desirable as even a thin shoe adds to the weight, and on a hand manipulated screed of this character, a minimum of weight with effectiveness is a desirable characteristic.

The particular handle structure and mounting provides for easy balancing and manipulation of the screed and also, the connections for the handle to the screed are such as to effective y absorb and minimize vibration transmitted to the operator. The feature of adjustability of the handle shafts to each other eliminates the necessity for great accuracy in the thickness of the screed and in fact the handles may be readily adjusted to screed members at any desiredthickness. The propelling force referred to is sufficient to strike off a substantial amount of low slump concrete without particular effort on the part of the operator aside from holding the machine in upright position. and this is true even though the vibratory impulses are of very low amplitude.

I have illustrated and described my im rovements in embodiments thereof which I have found very desirable commercially. I have not attempted to illustrate various embodiment or adaptations that may be made as it is believed that this disclosure will enable those skilled in the art to embody or adapt my improvements as may be desired.

Having thus described my invention, what I through the screed member and brackets, flexible tubular support member of substantial length telescopingly engaged with said studs of the pairs of brackets and clamped thereon, vertically disposed handle coupling members clamped upon said flexible support members intermediate the ends thereof and in substantially spaced relation to said brackets, handles at each end of said screed member comprising pairs of handle shafts and handle bars to which the outer ends of said handle shafts are adjustably connected whereby the spaced relation of the shafts relative to each other may be varied, pivots connecting said handle shafts to said handle shaft coupling members, said coupling members having segmental slots concentric with said pivots, and bolts on said handle shafts adjustably engaging said slots whereby the handles may be adjusted in their angular relation to the screed and secured in their adjusted positions.

2. In a structure of the class described, the combination of a plank-like screed member disposed vertically edgewise, means for vibrating said screed member, angled brackets provided with studs disposed in coacting spaced pairs on both sides of the screed member adjacent each end thereof, corresponding brackets of the pairs on opposite sides of the screed member being aligned and being secured by bolts extending through the screed member and brackets, flexib e tubular su port members of substantial length tele c ingly engaged with said studs of the pairs of brackets and clamped thereon, handle coupling members clamped upon said flexible support members intermediate the ends thereof and n substantiallv spaced relation to said brackets, handles at each end of said screed member comprising pairs of handle shafts and handle bars to which the outer ends of saidhandle shafts are adjustably connected whereby the spaced relation of the shafts relative to each other may be varied, and encircling adjustable means for securing said handle shafts to said coupling members whereby the handles may be adjusted in their angular relation to the screed and secured in their adjusted positions. I v

3. In a structure of the class described, the combination of an elongated screed member disposed vertically edgewise, means for vibrating said screed member comprising an unbalanced rotor bolted to one side of said screed member with its axis longitudinally thereof, brackets provided with studs mounted in coacting spaced pairs on both sides of the screed member adjacent each end thereof, flexible tubular support members of substantial length telescopingly engaged with said studs of the pairs of brackets and clamped thereon, handle coupling members secured to said flexible support members intermediate the ends thereof and in substantially spaced relation to said brackets, handles at each end of said screed member comprising pairs of handle shaft and handle bars at the outer ends of said handle shafts, and means for securing said handle shafts to said coupling members.

4. In a structure of the class described, the combination of a plank-like screed member of wood disposed vertically edgewise, means for vibrating said screed member at high frequency carried thereby, brackets disposed in coacting spaced pairs on both sides of the screed member adjacent each end thereof, correspondin brackets of the pairs on opposite sides of the screed member being aligned and being secured by bolts extending through the screed member and brack ets, flexible tubular support members of substantial length secured at their ends to said brackets, handle coupling members secured upon said flexible support members intermediate the ends thereof and in substantially spaced relation to said brackets, handles at each end of said screed member comprising pairs of handle shafts and handle bars at their outer ends, and means for securing said handle shafts to said coupling members.

5. In a structure of the class described, the combination of a plank-like screed member of Wood disposed vertically edgewise, means for vibrating said screed member comprising an unbalanced rotor bolted to one side of the screed member with its axis longitudinally thereof, handles at each end of said screed member comprising pairs of handle shafts and handle bars at their outer ends, said handle shafts being adjustably connected to said handle bars whereby the spaced relation of the shafts relative to each other may be varied, and connections for the inner ends of said handle shafts to the opposite sides of said screed member adjacent the opposite ends of the latter, comprising flexible nonelastic support members secured to the screed member, said handle shafts being connected to said support members by an angularly swingable connection to permit the angular adjustment of the handles relative to the screed member.

6. In a structure of the class described, the combination of a plank-like screed member of Wood disposed vertically edgewise, means for vibrating said screed member comprising an unbalanced rotor bolted to one side of the screed member with its axis longitudinally thereof, handles at each end of said screed member comprising pairs of handle shafts and handle bars at their outer ends, and connections for the inner ends of said handle shafts to the opposite sides of said screed member adjacent the opposite ends of the latter, comprising flexible non-elastic support members secured at their ends to the screed member and intermediate said ends to the handle shafts.

7. In a structure of the class described, the combination of a plank-like screed member of wood disposed vertically edgewise, means for vibrating said screed member at high frequency carried thereby, and handles at the ends of said screed member provided with transverse grip bars at their outer ends resiliently connected thereto, the connection comprising flexible nonextensible members secured at their ends to the sides of the screed in opposed relation, th handles being secured to said members intermediate and in substantially spaced relation to their end connections to said screed, the handle connections including means permitting the angular adjustment of the handles relative to the screed member.

8. In a structure of the class described, the combination of a plank-like screed member of wood disposed vertically edgewise, means for vibrating said screed member ,at high frequency carried thereby, and handles at the ends of said screed member provided with transverse grip bars at their outer ends resiliently connected thereto said handle connection comprising flexible non-extensible members secured at their ends to the sides of the screed in opposed relation, the handles being secured to said members intermediate their points of connection to the screed and in substantially spaced relation relative thereto.

9. In a structure of the class described, the combination of an elongated screed member disposed vertically edgewise, means carried by said screed member for vibrating the same at high frequency, member, and means at each of the opposite ends of said member connecting the handles thereto, including elongated resilient supports secured at the ends thereof to each side of the screed member adjacent said respective ends of the latter and means rigidly connecting said handles to said supports in spaced relation to the securement of the latter to the screed.

CORWILL JACKSON.

handles at each end of the screed 

